Short Notice for Disney and leaving in a few days, please help!

I just learnt that we will be in Orlando area around Oct 6th. Of course, we have to visit Disney. The last time we were there was 3 years ago and I bought Disney t-shirt from the outlet. The last time, I saw people wearing custom shirt and thought I will do that too when I visit Disney next time.

I have 3 boys ages almost 8, 6 and almost 5. Could you please advice on how to design it? Do you think I have time to do it?